Do Tree Swallows and Bluebirds Compete?
Competition exists when the niches of two species overlap. Both swallows and bluebirds obviously are dependent on cavities for nesting, but otherwise they are different in many of their survival strategies. Bluebirds feed on ground-dwelling insects while swallows feed on insects in the air. Given places to nest, they can coexist within an area quite effectively. It may even be beneficial for bluebirds to have swallows nearby to warn them of potential predators or danger. Box pairing allows the advantages of coexistence while reducing competition for nest places. Other Advantages of Pairing In areas with House Sparrows (Passer domesticus) box pairing may reduce the chance of sparrows destroying a bluebird nest. A sparrow may be more likely to kill established bluebirds (or swallows) at a single box than if an empty paired box exists nearby. If a sparrow begins a nest in an empty paired box, a trail monitor could remove the sparrow before it interferes with the nest of a native species.
